In the related art, when physical information is obtained and supplied to a processor, it is necessary to convert the analog output (an analog value) of the physical sensor to a digital value. To perform this conversion an amplification circuit is generally required to adjust the output of the sensor to an input signal specification of an analog-to-digital conversion circuit before A/D conversion is carried out.
Furthermore, output modes of the sensor are broadly classified into a voltage mode and a current mode. Therefore, it is necessary to arrange the amplification circuit according to various sensor outputs (a voltage and a current) and an AFE (analog front end) circuit using the amplification circuit, thereby causing an area occupied by the amplification circuit and the AFE circuit using the amplification circuit in a chip, to be enlarged.